In data communication systems, signals may be degraded by various sources, such as level shifters and other signal propagation paths. Signal degradation has various forms, among which, phase distortion is one of the most commonly observed. FIG. 1 illustrates an exemplary phase distortion of a signal. After an original signal is passed into a phase distortion path, a translated signal is generated. The original signal has a period Torg, and the translated signal has a period Ttrl. Typically, the periods Torg and Ttrl are measured corresponding to the mid-points of the signal transition edges. Due to mismatched rising delay Tdr and falling delay Tdf, periods Ttrl and Tper are different, hence the phase distortion. Typically, phase distortion PD can be expressed as:PD=|Torg−Ttrl|Torg  [Eq. 1]
For advanced circuits, such as high-speed applications, the phase distortion limits the operation speeds of the communication systems. Efforts have been taken to reduce the phase distortion. For example, complementary metal-oxide-semiconductor (CMOS) inverters with extreme P/N ratios have been designed, so that the periods of the signal are taken at points different from the mid-points of the transition edges. However, this solution suffers from process variations, voltage variations and temperature variations.
Additionally, circuits using current-mode amplification have been designed, wherein currents, instead of voltages, are used to represent signals. This type of circuit has high power consumption, since high currents are needed to represent high voltages.
The duty cycle correction mechanism has also been introduced, which can restore clock signals. However, this mechanism is not suitable for data communications, in which the signals are random, instead of having repeated patterns. In addition, circuits using the duty cycle connection mechanism also suffer from high power consumption.
Accordingly, what is needed in the art is a method for eliminating the phase distortion of signals while at the same time overcoming the deficiencies of the prior art.